18 GENERAL CHARACTERS OF VERTEBRATEP ANIMALS. 

 FIRST BRANCH 



OF THE 



ANIMAL KINGDOM. 



ANIMALIA VERTEBRATA. 



GENERAL CHARACTERS OF VERTEBRATED ANIMALS. 



18. The vertebrated animals are, of all animated beings, those 

 whose faculties are most various and most perfect ; whose organs 

 are most numerous and most complicated. 



19. The existence of a solid frame in the interior of the body 

 enables them to attain a size which the articulated animals, mol- 

 lusca and zoophytes never reach ; and this skeleton, all the parts 

 of which are united one to the other so as to allow of motion, 

 gives to their movements a precision and a vigour which are 

 rarely seen in other animals. 



20. The portion of the skeleton which is never wanting, which 

 varies least, and which is, at the same time, the most important of 

 all, is the bony stem that encloses the encephalon, and which is 

 formed by the cranium and vertebral column. 



21. The external senses are always five in number, and the 

 organs which are the seat of them, present with slight variation, 

 the same disposition as in man. 



What are the characters which distinguish animals belonging to the 

 branch of molluscous animals? How is this branch divided ? Have animals 

 of this branch a brain or spinal marrow ? What is the nature of their nervous 

 system? Do animals of this branch possess an internal skeleton ? 



What are the characters which distinguish animals belonging to the branch 

 of articulated animals? What is the character of the nervous system of this 

 branch? Has this branch an internal skeleton ? What kind of blood do 

 animals of this branch possess ? What classes of animals are included in 

 this branch? 



What are the characters which distinguish animals of the branch of radiated 

 animals? What is the form of the bodies of animals of this branch? 

 What is the character of their nervous system ? Have these animals a 

 heart? What is the color of their blood ? What classes does this branch 

 include ? 



18. What branch of the animal kingdom includes the most perfectly or- 

 ganised animals ? 



19. What are the chief advantages derived from an internal skeleton by 

 animals of the branch of vertebrata? 



20. What part of the skeleton is never absent in the vertebrated animals ? 



21. What is the number of the senses in the vertebrata? What is their 

 disposition ? [See Physiology and Animal Mechanism Lesson viii. and is.. 



